"He writes a book."
Translation:Lui scrive un libro.
If "he" writes, shouldn't "lui" be required, as without it the sentence is ambiguous as to "he" or "she"?
It's not required in Italian. It could be ambiguous or it could make perfect sense in context.
In Italian the i sounds like e and e sounds like a I sometimes have the same problem. Hope this helps
I personally think that it should be "lui" because "lui" is one of the many pronouns of he